Pigment



35 by weight, of the mix and the remainder the which are employed in making the pigment 35 other finely divided iron. They may each con- Pyl'ites cinder, which 13 an r compound tit t 50% of t ferrous t The f r... can be mixed with the dilute solution of sulmus compound t obtained is mixed with the phuric acid, or another mineral acid, the carbon a bd in various pmportions, fo example; or sulphur compounds added, then dried and 40 calcined. 40 7""'7"" to by ig Ordinarily, the pyrites cinder will be obtained Ferrous mammal 70% to 995% from iron pyrites, after the sulphur has been re- The carbon and ferrous material will be finely moved by bu n g I divided and then calcined for a period of two or I claim as my vention: i 45 three hours at from 1200 F. to 1500 F. The method of producing an iron oxide pig- 45 PatentedJune 11, 1940 i i UNITED STATES PATENT OFFICE 2,203,905 PIGMENT Joseph C. Heckman, Pittsburgh, Pa.

No Drawing. Application June 21, 1937, Serial No. 149,435. Renewed October 21, 1939 ,1 Claim. (01. 134-59) My invention relates to pigments such as are firing at the lower temperatures for a longer employed in coloring or tinting, or as polishing period of time produces a brighter color than does rouges etc. i a shorter firing period at higher temperatures.

The invention has for its object the making of Instead of carbon, or in addition to carbon, pigment products of high quality and desired spent oxide of iron from gas manufacturing 5 shades which can be produced largely from waste p y be included With the ferrous m materials which contain high percentages of iron. rial D V t0 firing, in percentages of P p In its preferredembodiment, my invention infrom .5% to p The Sulphur cludes the use of a sulphate of iron, finely dip c a different Shade in the Pigment h 19 vided iron oxide such as iron sludge or blast does the carbon. Where the carbon in small furnace flue dust, and carbon, all mixed toquantities will give a yellowish tone to the red gether and calcined. Various detailed aspects i n the sulphur w p u more of a blue of the invention are hereinafter set forth. t ne there The sulphate of iron preferably will be in The spent oxide of iron flbOVG referredto is the form of sludge such as settles or is precipip10 ee in large quantities as a Waste Product 15 tated fro the ate drainage i sid f a d in the manufacturing of artificial gas. A typical emitted from coal mines, and contains a conanalysis Of this product is as follows; siderable percentage (26% to 31%) of sulphur. Per cent This is commonly called coal mine sulphur mud. Ferric oxide 26 71 Other forms of sulphate of iron such as cop- Sulphur 48'56 20 peras may be employed insteadof the coal-mine sulphate of iron. Tar 7 The finely divided iron oxide may be a waste "7"? f 'T product such as iron sludge, blast furnace flue The cyamdes referred to in Sald analysls dust, or other iron residues, or may be hydrated ally are in the form of term cyanide potassium 25 oxide f iron or iron ore" which sometimes turns into Prussian blue.

'I'he carbon constituent may include finely The Value of Waste product in the making vid d w d, h as Sawdust, wood flour and wood of pigments is to a large degree attributable to wool; bituminous or anthracite coal; coal pyrites; the Presence therein 0f the Said y e becoke; charcoal; bone black, r Similar volatile cause they greatly enhance the brilliancy of color 30 mat ri l, in ferrous sulphates and other forms of oxides The sulphate of iron and the oth f rrous or of iron. Furthermore, a variety of brilliantred iron-containing materials can be mixed together, Shades may e Obtained by the use Of the ath ulphate of iron t t t 1 to 0 terial, by varying the percentage of spent oxides Theferrous material alone when calcined will ment material W ehe mprises making a mixbe ofagood red color. The carbon content when ture containing 88% to 99.5% ferrous sulphate calcined with the ferrous material greatly enand .5% to 12% spent oxides of iron from artiriches the color, producing a variety of shades ficial gas plan by. Wei t, and al nin the which are not possible with ferrous material mixture. H I 50 alone, and the percentage of carbon will be varied JOSEPH C. HECKMAN. in accordance with the shade desired. Also, the l 

